DaveK

Hi,
I know that noises are hard to describe over the internet, but I'll try.....

It's kind of a hollow knocking - bit like someone knocking on one of the side windows.

I have had a similar noise about half a dozen times since buying the car (2.5 years ago) but it never stayed around long enough to be found - and didn't used to be related to wheel speed.

This time, it does seem to be related to wheel speed. It often does it when cornering, but the way to repeat it 100% is to slow down - don't have to be braking, just remove my foot from the pedal and it will start.

Sounds like it comes from the rear of the car. Is doing it pretty constantly so it looks like the car will have to go to the garage (it needs a new evaporator and alignment anyway...) but I'd like some ideas first.

I assumed wheel bearing at first but not so sure since I can't hear it so much when at a constant speed / accelerating (slowly) from stop.

Arjan B.

A wheel bearing does not stop making noice, once broke, the sound will stay. Do you have something in your tire profile, a stone or a screw in your tyre??
Check the drive shafts also for evt. too much space on it.

DaveK

My mechanic also said wheel bearings groan, not knock. Can't see anything in the tyre.

What do you mean about the drive shaft? What do I check?

One thing I forgot to mention - seems to do it in neutral as well as in gear.

mark964

Does it make the noise with the engine off? Get up some speed and turn off the engine. just don't lock the steering wheel. Do some turns etc. If you still get noise, then I would suspect your CV joints. Your mechanic is right about the wheel bearings and groaning. Clicking is more symptomatic of CV joints.

If you don't get any of the noises you describe with the car moving but engine off, then it's possible that it's your flywheel. The typical symptoms with the DMF is a nasty clunking at startup, shutdown and reducing speed. However, these are not the only symptoms of a failed flywheel. You can get other symptoms which will cause you to suspect wheel bearings and/or CV joints. Another member has submitted a flywheel post on this.

Good luck

DaveK

If it was the flywheel, wouldn't it be related to engine speed not wheel speed? So if I put it in neutral and coast (which I did this morning) then I would expect it to slow down to match the idle speed of the engine rather than matching the wheel speed?

Arjan B.

I ment the drive shafts which come out of the gear box and go to your wheel. Her are joint, which could have too much play. Internal the joints will move up and down which will cause a knocking noice. The joints are protected by "condoms" agains sand and dust. Look on www.spidan.com for an example.

Arjan B.

Sorry, site is not right.

DaveK

I've had the car up on axle stands with the wheels off and nothing obvious. The drive shafts move in and out, but not up and down - and I assume that's normal (although when you move them in / out they do make a knocking noise at the end of their travel).